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1.
Int J Mol Sci ; 21(17)2020 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-32842637

RESUMO

Polycystic ovarian syndrome (PCOS) is the main cause of female infertility. It is a multifactorial disorder with varying clinical manifestations including metabolic/endocrine abnormalities, hyperandrogenism, and ovarian cysts, among other conditions. D-Chiro-inositol (DCI) is the main treatment available for PCOS in humans. To address some of the mechanisms of this complex disorder and its treatment, this study examines the effect of DCI on reproduction during the development of different PCOS-associated phenotypes in aged females and two mouse models of PCOS. Aged females (8 months old) were treated or not (control) with DCI for 2 months. PCOS models were generated by treatment with dihydrotestosterone (DHT) on Days 16, 17, and 18 of gestation, or by testosterone propionate (TP) treatment on the first day of life. At two months of age, PCOS mice were treated with DCI for 2 months and their reproductive parameters analyzed. No effects of DCI treatment were produced on body weight or ovary/body weight ratio. However, treatment reduced the number of follicles with an atretic cyst-like appearance and improved embryo development in the PCOS models, and also increased implantation rates in both aged and PCOS mice. DCI modified the expression of genes related to oocyte quality, oxidative stress, and luteal sufficiency in cumulus-oocyte complexes (COCs) obtained from the aged and PCOS models. Further, the phosphorylation of AKT, a main metabolic sensor activated by insulin in the liver, was enhanced only in the DHT group, which was the only PCOS model showing glucose intolerance and AKT dephosphorylation. The effect of DCI in the TP model seemed mediated by its influence on oxidative stress and follicle insufficiency. Our results indicate that DCI works in preclinical models of PCOS and offer insight into its mechanism of action when used to treat this infertility-associated syndrome.


Assuntos
Blastocisto/efeitos dos fármacos , Infertilidade Feminina/tratamento farmacológico , Inositol/farmacologia , Oócitos/efeitos dos fármacos , Síndrome do Ovário Policístico/tratamento farmacológico , Envelhecimento , Animais , Blastocisto/fisiologia , Células do Cúmulo/efeitos dos fármacos , Di-Hidrotestosterona/toxicidade , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Intolerância à Glucose/tratamento farmacológico , Infertilidade Feminina/etiologia , Infertilidade Feminina/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos Endogâmicos , Oócitos/fisiologia , Fosforilação/efeitos dos fármacos , Síndrome do Ovário Policístico/induzido quimicamente , Síndrome do Ovário Policístico/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Propionato de Testosterona/toxicidade
2.
J Neurogenet ; 31(4): 189-202, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28838288

RESUMO

Friedreich ataxia (FRDA) is the most important autosomal recessive ataxia in the Caucasian population. FRDA patients display severe neurological and cardiac symptoms that reflect a strong cellular and axonal degeneration. FRDA is caused by a loss of function of the mitochondrial protein frataxin which impairs the biosynthesis of iron-sulfur clusters and in turn the catalytic activity of several enzymes in the Krebs cycle and the respiratory chain leading to a diminished energy production. Although FRDA is due to frataxin depletion, overexpression might also be very helpful to better understand cellular functions of frataxin. In this work, we have increased frataxin expression in neurons to elucidate specific roles that frataxin might play in these tissues. Using molecular, biochemical, histological and behavioral methods, we report that frataxin overexpression is sufficient to increase oxidative phosphorylation, modify mitochondrial morphology, alter iron homeostasis and trigger oxidative stress-dependent cell death. Interestingly, genetic manipulation of mitochondrial iron metabolism by silencing mitoferrin successfully improves cell survival under oxidative-attack conditions, although enhancing antioxidant defenses or mitochondrial fusion failed to ameliorate frataxin overexpression phenotypes. This result suggests that cell degeneration is directly related to enhanced incorporation of iron into the mitochondria. Drosophila frataxin overexpression might also provide an alternative approach to identify processes that are important in FRDA such as changes in mitochondrial morphology and oxidative stress induced cell death.


Assuntos
Morte Celular/genética , Proteínas de Drosophila/genética , Proteínas de Ligação ao Ferro/genética , Ferro/metabolismo , Neurônios/metabolismo , Estresse Oxidativo/genética , Animais , Animais Geneticamente Modificados , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Homeostase/genética , Proteínas de Ligação ao Ferro/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Fosforilação Oxidativa , Frataxina
4.
J Neurochem ; 131(3): 369-82, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25040725

RESUMO

Drosophila melanogaster has contributed significantly to the understanding of disease mechanisms in Parkinson's disease (PD) as it is one of the very few PD model organisms that allow the study of age-dependent behavioral defects, physiology and histology, and genetic interactions among different PD-related genes. However, there have been contradictory results from a number of recent reports regarding the loss of dopaminergic neurons in different PD fly models. In an attempt to re-evaluate and clarify this issue, we have examined three different genetic (α-synuclein, Pink1, parkin) and two toxin-based (rotenone and paraquat) models of the disease for neuronal cell loss. Our results showed no dopaminergic neuronal loss in all models tested. Despite this surprising result, we found additional phenotypes showing the dysfunctional status of the dopaminergic neurons in most of the models analyzed. A common feature found in most models is a quantifiable decrease in the fluorescence of a green-fluorescent protein reporter gene in dopaminergic neurons that correlates well with other phenotypes found for these models and can be reliably used as a hallmark of the neurodegenerative process when modeling diseases affecting the dopaminergic system in Drosophila. Analyzing three genetic and two toxin-based Drosophila models of Parkinson's disease (PD) through green fluorescent protein reporter and α-tyrosine hydroxylase staining, we have found the number of dopaminergic neurons to remain unchanged. Despite the lack of neuronal loss, we have detected a remarkable decrease in a reporter green-fluorescent protein (GFP) signal in dopaminergic neurons, suggesting an abnormal neuronal status that correlates with the phenotypes associated with those PD fly models.


Assuntos
Neurônios Dopaminérgicos/efeitos dos fármacos , Drosophila/fisiologia , Doença de Parkinson Secundária/patologia , Doença de Parkinson/patologia , Animais , Contagem de Células , Proteínas de Drosophila/biossíntese , Proteínas de Drosophila/genética , Mutação/genética , Doenças Neurodegenerativas/induzido quimicamente , Doenças Neurodegenerativas/patologia , Doença de Parkinson/genética , Doença de Parkinson Secundária/induzido quimicamente , Proteínas Serina-Treonina Quinases/biossíntese , Proteínas Serina-Treonina Quinases/genética , Transdução de Sinais/genética , Ubiquitina-Proteína Ligases/biossíntese , Ubiquitina-Proteína Ligases/genética , alfa-Sinucleína/biossíntese , alfa-Sinucleína/genética
5.
Hum Mol Genet ; 19(14): 2828-40, 2010 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-20460268

RESUMO

Friedreich's ataxia (FRDA) is the most common form of autosomal recessive ataxia caused by a deficit in the mitochondrial protein frataxin. Although demyelination is a common symptom in FRDA patients, no multicellular model has yet been developed to study the involvement of glial cells in FRDA. Using the recently established RNAi lines for targeted suppression of frataxin in Drosophila, we were able to study the effects of general versus glial-specific frataxin downregulation. In particular, we wanted to study the interplay between lowered frataxin content, lipid accumulation and peroxidation and the consequences of these effects on the sensitivity to oxidative stress and fly fitness. Interestingly, ubiquitous frataxin reduction leads to an increase in fatty acids catalyzing an enhancement of lipid peroxidation levels, elevating the intracellular toxic potential. Specific loss of frataxin in glial cells triggers a similar phenotype which can be visualized by accumulating lipid droplets in glial cells. This phenotype is associated with a reduced lifespan, an increased sensitivity to oxidative insult, neurodegenerative effects and a serious impairment of locomotor activity. These symptoms fit very well with our observation of an increase in intracellular toxicity by lipid peroxides. Interestingly, co-expression of a Drosophila apolipoprotein D ortholog (glial lazarillo) has a strong protective effect in our frataxin models, mainly by controlling the level of lipid peroxidation. Our results clearly support a strong involvement of glial cells and lipid peroxidation in the generation of FRDA-like symptoms.


Assuntos
Modelos Animais de Doenças , Drosophila , Ataxia de Friedreich/genética , Ataxia de Friedreich/patologia , Transtornos do Metabolismo dos Lipídeos/complicações , Animais , Animais Geneticamente Modificados , Proteínas de Transporte/genética , Proteínas de Transporte/fisiologia , Sobrevivência Celular/genética , Drosophila/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiologia , Ácidos Graxos/sangue , Ataxia de Friedreich/complicações , Ataxia de Friedreich/metabolismo , Humanos , Proteínas de Ligação ao Ferro/genética , Proteínas de Ligação ao Ferro/metabolismo , Proteínas de Ligação ao Ferro/fisiologia , Transtornos do Metabolismo dos Lipídeos/genética , Transtornos do Metabolismo dos Lipídeos/metabolismo , Transtornos do Metabolismo dos Lipídeos/patologia , Peroxidação de Lipídeos/genética , Peroxidação de Lipídeos/fisiologia , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/fisiologia , Sistema Nervoso/metabolismo , Sistema Nervoso/patologia , Neuroglia/metabolismo , Neuroglia/fisiologia , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , Frataxina
6.
Pharmaceutics ; 14(8)2022 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-36015220

RESUMO

The widespread use of added sugars or non-nutritive sweeteners in processed foods is a challenge for addressing the therapeutics of obesity and diabetes. Both types of sweeteners generate health problems, and both are being blamed for multiple complications associated with these prevalent diseases. As an example, fructose is proven to contribute to obesity and liver steatosis, while non-nutritive sweeteners generate gut dysbiosis that complicates the metabolic control exerted by the liver. The present work explores an alternative approach for sweetening through the use of a simple carob-pod-derived syrup. This sweetener consists of a balanced mixture of fructose (47%) and glucose (45%), as sweetening sugars, and a functional natural ingredient (D-Pinitol) at a concentration (3%) capable of producing active metabolic effects. The administration of this syrup to healthy volunteers (50 g of total carbohydrates) resulted in less persistent glucose excursions, a lower insulin response to the hyperglycemia produced by its ingestion, and an enhanced glucagon/insulin ratio, compared to that observed after the ingestion of 50 g of glucose. Daily administration of the syrup to Wistar rats for 10 days lowered fat depots in the liver, reduced liver glycogen, promoted fat oxidation, and was devoid of toxic effects. In addition, this repeated administration of the syrup improved glucose handling after a glucose (2 g/kg) load. Overall, this alternative functional sweetener retains the natural palatability of a glucose/fructose syrup while displaying beneficial metabolic effects that might serve to protect against the progression towards complicated obesity, especially the development of liver steatosis.

7.
Nutrients ; 14(19)2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-36235746

RESUMO

The present study characterizes the oral pharmacokinetics of D-Pinitol, a natural insulin mimetic inositol, in human healthy volunteers (14 males and 11 females). D-Pinitol absorption was studied in (a) subjects receiving a single oral dose of 15 mg/kg (n = 10), or (b) 5 mg/kg pure D-Pinitol (n = 6), and (c) subjects receiving D-Pinitol as part of carbohydrate-containing carob pods-derived syrup with a 3.2% D-Pinitol (Dose of 1600 mg/subject, n = 9). The volunteers received a randomly assigned single dose of either D-Pinitol or carob pod-derived syrup. Blood samples were collected at 0, 15, 30, 45, 60, 90, 120, 180, 240, 360 and 1440 min after intake. Plasma concentration of D-Pinitol was measured and pharmacokinetic parameters obtained. The data indicate that when given alone, the oral absorption of D-Pinitol is dose-dependent and of extended duration, with a Tmax reached after almost 4 h, and a half-life greater than 5 h. When the source of D-Pinitol was a carob pods-derived syrup, Cmax was reduced to 40% of the expected based on the data of D-Pinitol alone, suggesting a reduced absorption probably because of competition with monosaccharide transport. In this group, Tmax was reached before that of D-Pinitol alone, but the estimated half-life remained the same. In the D-Pinitol groups, plasma concentrations of glucose, insulin, glucagon, ghrelin, free fatty acids, and pituitary hormones were additionally measured. A dose of 15 mg/kg of D-Pinitol did not affect glucose levels in healthy volunteers, but reduced insulin and increased glucagon and ghrelin concentrations. D-Pinitol did not increase other hormones known to enhance plasma glucose, such as cortisol or GH, which were surprisingly reduced after the ingestion of this inositol. Other pituitary hormones (gonadotropins, prolactin, and thyroid-stimulating hormone) were not affected after D-Pinitol ingestion. In a conclusion, D-Pinitol is absorbed through the oral route, having an extended half-life and displaying the pharmacological profile of an endocrine pancreas protector, a pharmacological activity of potential interest for the treatment or prevention of insulin resistance-associated conditions.


Assuntos
Fabaceae , Jejum , Glicemia , Ácidos Graxos não Esterificados , Feminino , Grelina , Glucagon , Glucose , Voluntários Saudáveis , Humanos , Hidrocortisona , Inositol/análogos & derivados , Insulina , Masculino , Prolactina , Tireotropina
8.
Nefrologia (Engl Ed) ; 2021 Jan 28.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-33781578

RESUMO

We present the case of a male patient with severe SARS-CoV-2 pneumonia, with simultaneous onset of p-ANCA positive rapidly progressive glomerulonephritis. We discuss the different therapeutic possibilities, emphasising the appropriateness of their administration according to the time in the course of the infection.

9.
Thromb Res ; 199: 132-142, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33503547

RESUMO

BACKGROUND: Incidence of thrombotic events associated to Coronavirus disease-2019 (COVID-19) is difficult to assess and reported rates differ significantly. Optimal thromboprophylaxis is unclear. OBJECTIVES: We aimed to analyze the characteristics of patients with a confirmed thrombotic complication including inflammatory and hemostatic parameters, compare patients affected by arterial vs venous events and examine differences between survivors and non-survivors. We reviewed compliance with thromboprophylaxis and explored how the implementation of a severity-adjusted protocol could have influenced outcome. METHODS: Single-cohort retrospective study of COVID-19 patients admitted, from March 3 to May 3 2020, to the Infanta Leonor University Hospital in Madrid, epicenter of the Spanish outbreak. RESULTS: Among 1127 patients, 80 thrombotic events were diagnosed in 69 patients (6.1% of the entire cohort). Forty-three patients (62%) suffered venous thromboembolism, 18 (26%) arterial episodes and 6 (9%) concurrent venous and arterial thrombosis. Most patients (90%) with a confirmed thrombotic complication where under low-molecular-weight heparin treatment. Overt disseminated intravascular coagulation (DIC) was rare. Initial ISTH DIC score and pre-event CRP were significantly higher among non-survivors. In multivariate analysis, arterial localization was an independent predictor of mortality (OR = 18, 95% CI: 2.4-142, p < .05). CONCLUSIONS: Despite quasi-universal thromboprophylaxis, COVID-19 lead to a myriad of arterial and venous thrombotic events. Considering the subgroup of patients with thrombotic episodes, arterial events appeared earlier in the course of disease and conferred very poor prognosis, and an ISTH DIC score ≥ 3 at presentation was identified as a potential predictor of mortality. Severity-adjusted thromboprophylaxis seemed to decrease the number of events and could have influenced mortality. Randomized controlled trials are eagerly awaited.


Assuntos
Anticoagulantes/uso terapêutico , COVID-19/complicações , Heparina de Baixo Peso Molecular/uso terapêutico , Trombose/tratamento farmacológico , Trombose/etiologia , Idoso , Idoso de 80 Anos ou mais , Coagulação Intravascular Disseminada/diagnóstico , Coagulação Intravascular Disseminada/tratamento farmacológico , Coagulação Intravascular Disseminada/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , SARS-CoV-2/isolamento & purificação , Trombofilia/diagnóstico , Trombofilia/tratamento farmacológico , Trombofilia/etiologia , Trombose/diagnóstico , Tromboembolia Venosa/diagnóstico , Tromboembolia Venosa/tratamento farmacológico , Tromboembolia Venosa/etiologia
10.
Redox Biol ; 37: 101762, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33128998

RESUMO

Friedreich ataxia (FRDA) is a neurodegenerative disorder characterized by neuromuscular and neurological manifestations. It is caused by mutations in the FXN gene, which results in loss of the mitochondrial protein frataxin. Endoplasmic Reticulum-mitochondria associated membranes (MAMs) are inter-organelle structures involved in the regulation of essential cellular processes, including lipid metabolism and calcium signaling. In the present study, we have analyzed in both, unicellular and multicellular models of FRDA, calcium management and integrity of MAMs. We observed that function of MAMs is compromised in our cellular model of FRDA, which was improved upon treatment with antioxidants. In agreement, promoting mitochondrial calcium uptake was sufficient to restore several defects caused by frataxin deficiency in Drosophila Melanogaster. Remarkably, our findings describe for the first time frataxin as a member of the protein network of MAMs, where interacts with two of the main proteins implicated in endoplasmic reticulum-mitochondria communication. These results suggest a new role of frataxin, indicate that FRDA goes beyond mitochondrial defects and highlight MAMs as novel therapeutic candidates to improve patient's conditions.


Assuntos
Ataxia de Friedreich , Animais , Cálcio/metabolismo , Drosophila melanogaster/genética , Retículo Endoplasmático , Ataxia de Friedreich/genética , Ataxia de Friedreich/metabolismo , Mitocôndrias/metabolismo , Estresse Oxidativo
11.
Cell Rep ; 30(8): 2627-2643.e5, 2020 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-32101741

RESUMO

The conserved Hedgehog signaling pathway has well-established roles in development. However, its function during adulthood remains largely unknown. Here, we investigated whether the Hedgehog signaling pathway is active during adult life in Drosophila melanogaster, and we uncovered a protective function for Hedgehog signaling in coordinating correct proteostasis in glial cells. Adult-specific depletion of Hedgehog reduces lifespan, locomotor activity, and dopaminergic neuron integrity. Conversely, increased expression of Hedgehog extends lifespan and improves fitness. Moreover, Hedgehog pathway activation in glia rescues the lifespan and age-associated defects of hedgehog mutants. The Hedgehog pathway regulates downstream chaperones, whose overexpression in glial cells was sufficient to rescue the shortened lifespan and proteostasis defects of hedgehog mutants. Finally, we demonstrate the protective ability of Hedgehog signaling in a Drosophila Alzheimer's disease model expressing human amyloid beta in the glia. Overall, we propose that Hedgehog signaling is requisite for lifespan determination and correct proteostasis in glial cells.


Assuntos
Drosophila melanogaster/metabolismo , Proteínas Hedgehog/metabolismo , Longevidade , Neuroglia/metabolismo , Proteostase , Transdução de Sinais , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/metabolismo , Sobrevivência Celular , Modelos Animais de Doenças , Neurônios Dopaminérgicos/metabolismo , Homeostase , Humanos , Modelos Biológicos , Mutação/genética , Neurônios/metabolismo , Neuroproteção , Análise de Sobrevida
12.
Nutrients ; 12(7)2020 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-32650579

RESUMO

To characterize the metabolic actions of D-Pinitol, a dietary inositol, in male Wistar rats, we analyzed its oral pharmacokinetics and its effects on (a) the secretion of hormones regulating metabolism (insulin, glucagon, IGF-1, ghrelin, leptin and adiponectin), (b) insulin signaling in the liver and (c) the expression of glycolytic and neoglucogenesis enzymes. Oral D-Pinitol administration (100 or 500 mg/Kg) resulted in its rapid absorption and distribution to plasma and liver compartments. Its administration reduced insulinemia and HOMA-IR, while maintaining glycaemia thanks to increased glucagon activity. In the liver, D-Pinitol reduced the key glycolytic enzyme pyruvate kinase and decreased the phosphorylation of the enzymes AKT and GSK-3. These observations were associated with an increase in ghrelin concentrations, a known inhibitor of insulin secretion. The profile of D-Pinitol suggests its potential use as a pancreatic protector decreasing insulin secretion through ghrelin upregulation, while sustaining glycaemia through the liver-based mechanisms of glycolysis control.


Assuntos
Fabaceae/química , Grelina/sangue , Inositol/análogos & derivados , Secreção de Insulina/efeitos dos fármacos , Fígado/metabolismo , Administração Oral , Animais , Depressão Química , Grelina/metabolismo , Glucagon/metabolismo , Glicogênio/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Glicólise , Inositol/administração & dosagem , Inositol/isolamento & purificação , Inositol/farmacocinética , Inositol/farmacologia , Masculino , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Piruvato Quinase/metabolismo , Ratos Wistar
13.
Biology (Basel) ; 9(11)2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-33167441

RESUMO

Alzheimer's disease (AD) is the most common form of neurodegeneration and dementia. The endocannabinoid (ECB) system has been proposed as a novel therapeutic target to treat AD. The present study explores the expression of the ECB system, the ECB-related receptor GPR55, and cognitive functions (novel object recognition; NOR) in the 5xFAD (FAD: family Alzheimer's disease) transgenic mouse model of AD. Experiments were performed on heterozygous (HTZ) and homozygous (HZ) 11 month old mice. Protein expression of ECB system components, neuroinflammation markers, and ß-amyloid (Aß) plaques were analyzed in the hippocampus. According to the NOR test, anxiety-like behavior and memory were altered in both HTZ and HZ 5xFAD mice. Furthermore, both animal groups displayed a reduction of cannabinoid (CB1) receptor expression in the hippocampus, which is related to memory dysfunction. This finding was associated with indirect markers of enhanced ECB production, resulting from the combination of impaired monoacylglycerol lipase (MAGL) degradation and increased diacylglycerol lipase (DAGL) levels, an effect observed in the HZ group. Regarding neuroinflammation, we observed increased levels of CB2 receptors in the HZ group that positively correlate with Aß's accumulation. Moreover, HZ 5xFAD mice also exhibited increased expression of the GPR55 receptor. These results highlight the importance of the ECB signaling for the AD pathogenesis development beyond Aß deposition.

14.
Nefrologia (Engl Ed) ; 40(3): 345-350, 2020.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-31351697

RESUMO

The relationship between parasites and glomerulonephritis (GN) is well documented in certain parasitoses, but not in cases of Strongyloides stercolaris (S. stercolaris) where there are few cases described being the majority GN of minimal changes. We report a case of hyperinfestation by S. stercolaris in a patient affected by a membranous GN treated with oral corticosteroids with fatal outcome for the patient. This case provides a double teaching: first about a rare association of strongyloid and membranous GN and second about the importance of establishing a diagnosis of suspected and appropriate treatment for certain infections or diseases with little clinical expression before starting any immunosuppressive treatment.


Assuntos
Glomerulonefrite Membranosa/complicações , Imunossupressores/efeitos adversos , Prednisona/efeitos adversos , Strongyloides stercoralis , Estrongiloidíase/complicações , Síndrome de Resposta Inflamatória Sistêmica/etiologia , Animais , Criptococose/complicações , Diagnóstico Tardio , Quimioterapia Combinada , Equador/etnologia , Enterococcus faecium , Infecções por Escherichia coli/complicações , Evolução Fatal , Glomerulonefrite Membranosa/tratamento farmacológico , Glomerulonefrite Membranosa/urina , Infecções por Bactérias Gram-Positivas/complicações , Humanos , Hospedeiro Imunocomprometido , Imunossupressores/uso terapêutico , Pneumopatias Fúngicas/complicações , Masculino , Meningites Bacterianas/complicações , Pessoa de Meia-Idade , Pneumonia Bacteriana/complicações , Prednisona/uso terapêutico , Choque Séptico/etiologia , Espanha , Stenotrophomonas maltophilia , Estrongiloidíase/diagnóstico
15.
Sci Rep ; 10(1): 14912, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32913249

RESUMO

The controls that affect the structure and timing of terminations are still poorly understood. We studied a tufa deposit from the Iberian Peninsula that covers Termination II (T-II) and whose chronology was synchronized to speleothem records. We used the same chronology to synchronize ocean sediments from the North Atlantic to correlate major climate events in a common timescale. We identify two stages within T-II. The first stage started with the increase of boreal summer integrated solar insolation, and during this stage three millennial climate oscillations were recorded. These oscillations resulted from complex ocean-atmosphere interactions in the Nordic seas, caused by the progressive decay of Northern Hemisphere ice-sheets. The second stage commenced after a glacial outburst that caused the collapse of the Thermohaline Circulation, a massive Heinrich event, and the onset of the Bipolar Seesaw Mechanism (BSM) that eventually permitted the completion of T-II. The pace of the millennial oscillations during the first stage of T-II controlled the onset of the second stage, when the termination became a non-reversible and global phenomenon that accelerated the deglaciation. During the last the two terminations, the BSM was triggered by different detailed climate interactions, which suggests the occurrence of different modes of terminations.

16.
FASEB J ; 21(2): 333-44, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17167074

RESUMO

Friedreich ataxia (FA), the most common form of hereditary ataxia, is caused by a deficit in the mitochondrial protein frataxin. While several hypotheses have been suggested, frataxin function is not well understood. Oxidative stress has been suggested to play a role in the pathophysiology of FA, but this view has been recently questioned, and its link to frataxin is unclear. Here, we report the use of RNA interference (RNAi) to suppress the Drosophila frataxin gene (fh) expression. This model system parallels the situation in FA patients, namely a moderate systemic reduction of frataxin levels compatible with normal embryonic development. Under these conditions, fh-RNAi flies showed a shortened life span, reduced climbing abilities, and enhanced sensitivity to oxidative stress. Under hyperoxia, fh-RNAi flies also showed a dramatic reduction of aconitase activity that seriously impairs the mitochondrial respiration while the activities of succinate dehydrogenase, respiratory complex I and II, and indirectly complex III and IV are normal. Remarkably, frataxin overexpression also induced the oxidative-mediated inactivation of mitochondrial aconitase. This work demonstrates, for the first time, the essential function of frataxin in protecting aconitase from oxidative stress-dependent inactivation in a multicellular organism. Moreover our data support an important role of oxidative stress in the progression of FA and suggest a tissue-dependent sensitivity to frataxin imbalance. We propose that in FA, the oxidative mediated inactivation of aconitase, which occurs normally during the aging process, is enhanced due to the lack of frataxin.


Assuntos
Ataxia de Friedreich/genética , Proteínas de Ligação ao Ferro/genética , Estresse Oxidativo , Aconitato Hidratase/metabolismo , Animais , Western Blotting , Células CHO , Cricetinae , Cricetulus , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Ataxia de Friedreich/metabolismo , Ataxia de Friedreich/patologia , Expressão Gênica , Imuno-Histoquímica , Proteínas de Ligação ao Ferro/metabolismo , Proteínas de Ligação ao Ferro/fisiologia , Longevidade/genética , Proteínas Mitocondriais/metabolismo , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Succinato Desidrogenase/metabolismo , Frataxina
17.
Front Mol Neurosci ; 11: 38, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29563863

RESUMO

Friedreich's ataxia (FRDA) is the most important recessive ataxia in the Caucasian population. It is caused by a deficit of the mitochondrial protein frataxin. Despite its pivotal effect on biosynthesis of iron-sulfur clusters and mitochondrial energy production, little is known about the influence of frataxin depletion on homeostasis of the cellular mitochondrial network. We have carried out a forward genetic screen to analyze genetic interactions between genes controlling mitochondrial homeostasis and Drosophila frataxin. Our screen has identified silencing of Drosophila mitofusin (Marf) as a suppressor of FRDA phenotypes in glia. Drosophila Marf is known to play crucial roles in mitochondrial fusion, mitochondrial degradation and in the interface between mitochondria and endoplasmic reticulum (ER). Thus, we have analyzed the effects of frataxin knockdown on mitochondrial morphology, mitophagy and ER function in our fly FRDA model using different histological and molecular markers such as tetramethylrhodamine, ethyl ester (TMRE), mitochondria-targeted GFP (mitoGFP), p62, ATG8a, LAMP1, Xbp1 and BiP/GRP78. Furthermore, we have generated the first Drosophila transgenic line containing the mtRosella construct under the UAS control to study the progression of the mitophagy process in vivo. Our results indicated that frataxin-deficiency had a small impact on mitochondrial morphology but enhanced mitochondrial clearance and altered the ER stress response in Drosophila. Remarkably, we demonstrate that downregulation of Marf suppresses ER stress in frataxin-deficient cells and this is sufficient to improve locomotor dysfunction, brain degeneration and lipid dyshomeostasis in our FRDA model. In agreement, chemical reduction of ER stress by means of two different compounds was sufficient to ameliorate the effects of frataxin deficiency in three different fly FRDA models. Altogether, our results strongly suggest that the protection mediated by Marf knockdown in glia is mainly linked to its role in the mitochondrial-ER tethering and not to mitochondrial dynamics or mitochondrial degradation and that ER stress is a novel and pivotal player in the progression and etiology of FRDA. This work might define a new pathological mechanism in FRDA, linking mitochondrial dysfunction due to frataxin deficiency and mitofusin-mediated ER stress, which might be responsible for characteristic cellular features of the disease and also suggests ER stress as a therapeutic target.

19.
Sci Rep ; 8(1): 9858, 2018 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-29959379

RESUMO

Chronic NP-1 administration reduces body weight and hepatic steatosis despite induction of tolerance in adiponectin gene transcription with respect to the acute actions of this drug. This study explored the hypothesis that NP-1 could exert these effects through mechanisms independent of adiponectin. To this aim, we took advantage of the Zucker (fa/fa) rat model, which exhibits obesity, fatty liver and elevated leptin and adiponectin levels. Body weight and food intake were reduced after chronic NP-1 treatment. Plasma TNFα concentrations were elevated but no increase in adiponectin was found. Even so, NP-1 ameliorated fatty liver and corrected dyslipidemia by mechanisms probably associated with reduced feeding, transcription of Cpt1 and down-regulation of Hmgcr-CoA expression. In brown fat tissue NP-1 increased Dnmt1 (inhibitor of Adipoq) while it reduced Ucp1 expression and heat production, which excludes thermogenesis as a mechanism of the NP-1 slimming effect. The anti-obesity action of chronic NP-1 administration might be mediated by TNFα, which is known to have anorectic actions in the hypothalamus and to regulate both Dmnt1 and Ucp1 expression in adipose tissues. This finding opens up the possibility of using NP-1-mediated TNFα-induced weight loss as an innovative treatment of complicated obesity under strict pharmacologic control.


Assuntos
Adiponectina/metabolismo , Dislipidemias/prevenção & controle , Regulação da Expressão Gênica/efeitos dos fármacos , Obesidade/complicações , Tiazóis/farmacologia , Fator de Necrose Tumoral alfa/sangue , Adiponectina/genética , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Animais , Peso Corporal , DNA (Citosina-5-)-Metiltransferase 1/genética , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Dislipidemias/etiologia , Dislipidemias/metabolismo , Dislipidemias/patologia , Comportamento Alimentar , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Regiões Promotoras Genéticas , Ratos , Ratos Zucker , Magreza/complicações , Redução de Peso
20.
Front Genet ; 8: 223, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29312444

RESUMO

Maintenance of metal homeostasis is crucial for many different enzymatic activities and in turn for cell function and survival. In addition, cells display detoxification and protective mechanisms against toxic accumulation of metals. Perturbation of any of these processes normally leads to cellular dysfunction and finally to cell death. In the last years, loss of metal regulation has been described as a common pathological feature in many human neurodegenerative diseases. However, in most cases, it is still a matter of debate whether such dyshomeostasis is a primary or a secondary downstream defect. In this review, we will summarize and critically evaluate the contribution of Drosophila to model human diseases that involve altered metabolism of metals or in which metal dyshomeostasis influence their pathobiology. As a prerequisite to use Drosophila as a model, we will recapitulate and describe the main features of core genes involved in copper and zinc metabolism that are conserved between mammals and flies. Drosophila presents some unique strengths to be at the forefront of neurobiological studies. The number of genetic tools, the possibility to easily test genetic interactions in vivo and the feasibility to perform unbiased genetic and pharmacological screens are some of the most prominent advantages of the fruitfly. In this work, we will pay special attention to the most important results reported in fly models to unveil the role of copper and zinc in cellular degeneration and their influence in the development and progression of human neurodegenerative pathologies such as Parkinson's disease, Alzheimer's disease, Huntington's disease, Friedreich's Ataxia or Menkes, and Wilson's diseases. Finally, we show how these studies performed in the fly have allowed to give further insight into the influence of copper and zinc in the molecular and cellular causes and consequences underlying these diseases as well as the discovery of new therapeutic strategies, which had not yet been described in other model systems.

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